Module 10: Nervous System Flashcards
What are the two major divisions of the nervous system?
The central nervous system (CNS) and the peripheral nervous system (PNS)
What does the central nervous system consist of?
The brain and the spinal cord
What does the peripheral nervous system consist of?
Cranial nerves, spinal nerves, plexuses, and peripheral nerves
What is the 10th cranial nerve called?
The vagus nerve
What does the vagus nerve do?
Carries messages to and from the neck, chest, and abdomen
What do cranial nerves do? and which nerve is the exception?
Carry impulses between the brain and the head and neck, the vagus nerve is the exception
What do spinal nerves do?
They carry messages between the spinal cord and the chest, abdomen, and extremeties
Plexus
A large network of nerves in the peripheral nervous system
List 3 different Plexus networks
- cervical, 2. brachial, 3. lumbosacral, 4. lymphatic, 5. rectal, vertebral
What are sense receptors?
They are nerves that help the body respond to changes in the outside world
What are examples of sense receptors?
Sight, hearing, balance, smell (olfactory), and touch
What are sensory (afferent) nerves?
Nerves that carry messages related to changes in the environment TOWARD the spinal cord and brain
What are moto (efferent) nerves?
Nevers that travel FROM the spinal cord and brain to muscles of the body telling them how to respond
Vertebral plexus
a plexus of veins related to the backbone
rectal plexus
a plexus of veins in the rectal region
lymphatic plexus
an interconnecting network of lymph vessels
neuron
an individual nerve cell, a microscopic structure
stimulus
Begins an impulse in the branching fibers of the neuron called dendrites
dendrites
branching fibers of the neuron
cell body
contains the cell nucleus
ganglia (singular: ganglion)
small collections of nerve cell bodies outside the brain and spinal cord
axon
carries the impulse away from the cell body. They are covered with fatty tissue called myelin
what is the purpose of myelin sheath?
to insulate the axon and speed transmission of the electrical impulse. Gives a white appearance, hence the term white matter.
Demyelination
The loss of myelin insulating the nerve fiber and is a characteristic of multiple sclerosis
What is the gray matter of the brain and spinal cord?
It is composed of the cell bodies of the neurons that appear gray because they are not covered by a myelin sheath
terminal end fibers
nervus impulses pass through the axon to leave the cell via this structure at the end of the neuron
synapse
The space where the nervous impulse jumps from one neuron to another
neurotransmitter
the transfer of the impulse across the synapse depends on the release of a chemical substance that is released by the neuron that brings the impulse to the synapse
Where are the neurotransmitters located?
In tiny sacs (vesicles) containing the neurotransmitter are located at the ends of the neurons and they release the neurotransmitter into the synapse
List 6 types of neurotransmitters
acetylcholine, norepinephrine, epinephrine (adrenaline), dopamine, serotonin, and endorphines
nerve
a macroscopic structure within the nervous system
what does a nerve consist of?
consists of a bundle of dendrites and axons that travel together like strands of rope
where do peripheral nerves travel to?
They travel to the brain and spinal cord from stimulus receptors like the skin, eye, ear, and nose are afferent or sensory nerves
Afferent or sensory nerves
carry impulses from external organs to the brain and spinal cord (toward brain)
Efferent or motor nerves
carry impulses from the CNS to organs that produce responses such as muscles and glands (away from brain)
parenchyma
is the essential distinguishing tissue of an organ (e.g., in the brain and spinal cord, neurons are the parenchymal tissue)
stroma of an organ
is the connective and supportive tissue of an organ
what does the stromal tissue of the nervous system consist of?
glial (neuroglial) cells which make up its supportive framework and help it ward off infection.
Glial (neurological) cells
Make up the supportive framework of the stromal tissue in the nervous system, they do not transmit impulses, and they are far more numerous than neurons and can reproduce
What are the 4 types of supporting or glial cells?
- Astrocytes (astroglial cells) 2. microglial cells 3. oliodendroglial cells (oligodendrocytes) 4. ependymal cells
Astrocytes (astroglial cells)
star-like in appearance and transport water and salts between capillaries and neurons
astr/o
star
microglial cells
small cells with many branching processes (dendrites)
oligodendroglial cells (oligodendrocytes)
as phagocytes, they protect neurons in response to inflammation and have a few dendrites
olig/o
few or scanty
ependymal cells
line membranes within the brain and spinal cord where CSF is produced and circulates
Which glial cell is associated with blood vessels and regulate the passage of potentially harmful substances from the blood into the nerve cells of the brain?
astrocytes
blood-brain barrier (BBB)
a protective barrier between the blood and brain cells
What does the BBB consist of?
consists of a special lining (endothelial) cells, which along with astrocytes separate capillaries from nerve cells
How much does the brain weigh?
3 pounds
cerebrum
the largest part of the brain, the “thinking” area
cerebral cortex
on the surface of the cerebrum, nerve cells lie in sheets
gyri (plural: gyrus)
sheets in the cerebral cortex are arranged in folds and are separated from each other by grooves
sulci
grooves that separate the gyri
cerebral hemispheres
the right and left side of the brain
List the 4 lobes in the brain
frontal lobe, parietal lobe, temporal lobe, occipital lobe
What does the frontal lobe do?
responsible for thought processes, behaviour, personality, and emotion
What does the parietal lobe do?
responsible for body sensations, visual and spatial perception
What does the occipital lobe do?
responsible for vision
What does the temporal lobe do?
responsible for hearing, understanding speech, and language
ventricles
spaces or canals in the middle of the cerebrum
cerebrospinal fluid (CSF)
a watery fluid that flows throughout the brain and around the spinal cord
What is the purpose of the CSF?
it protects the brain and spinal cord from shock by acting like a cushion
What does CSF look like?
It is usually clear and colorless and contains lymphocytes, sugar, and proteins
lumbar puncture (LP)
A procedure in which spinal fluid can be withdrawn for diagnosis or relief of pressure on the brain.
how is the lumbar puncture performed?
It uses a hollow needle inserted into the lumbar region of the spinal column below the region where the nervous tissue of the spinal cord ends and the CSF is withdrawn
thalamus
a part of the brain that acts like a triage center. It decides what is important and what is not, selectively processing and relaying sensory information to the cerebral cortex
hypothalamus
(below the thalamus) contains neurons that control body temperature, sleep, appetite, sexual desire, and emotions such as fear and pleasure. It also regulates the release of hormones from the pituitary gland at the base of the brain and integrates activities of the sympathetic and parasympathetic nervous system
List the structures within the brain that lie in the back and below the cerebrum and connect the cerebrum with the spinal cord
cerebellum, pons, and medulla oblongata
What structures are part of the brainstem?
pons and medulla
cerebellum
functions to coordinate voluntary movements and to maintain balance and posture
pons
a part of the brainstem that literally means bridge. It contains nerve fiber tracts that connect the cerebellum and cerebrum with the rest of the brain (nerves to the eyes and face are here)
medulla oblongata
in the brainstem, connects the spinal cord with the rest of the brain. Nerve tracts across from right to left and left to right
What 3 important centers that regulate internal activities does the medulla oblongata contain?
- respiratory center, 2. cardiac center, 3. vasomotor center
respiratory center
controls muscles of respiration in response to chemicals or other stimuli
cardiac center
slows the heart rate when the heart is beating too rapidly
vasomotor center
affects (constricts or dilates) the muscles in the walls of blood vessels, thus influencing blood pressure
spinal cord
a column of nervous tissue extending from the medulla oblongata to the second lumbar vertebra within the vertebral column
cauda equina
the area below the end of the spinal cord, latin for “horse’s tail, is a fan of nerve fibers
What does the inner region of the spinal cord contain?
gray matter, containing cell bodies and dendrites
What does the outer region of the spinal cord contain?
white matter, containing the nerve fiber tracts with myelin sheaths
meninges
three layers of connective tissue membranes that surround the brain and spinal cord
What is the outermost membrane of the meninges called?
Dura matter
dura matter
a thick, tough membrane that contains channels (dural sinuses) that contain blood
What is the second layer surrounding the brain and spinal cord called?
Arachnoid membrane
arachnoid membrane
a (spider-like) membrane that is loosely attached to the other meninges by web-like fibers
What is the space for fluid between the arachnoid membrane web-like fibers called?
subarachnoid space
subarachnoid space
the space for fluid between the fibers of the arachnoid membrane containing CSF
What is the third layer of the meninges closest to the brain and spinal cord called?
pia mater
Pia mater
it contains delicate connective tissue with a rich supply of blood vessels
most physicians refer to the pia and arachnoid membranes together and call it what?
pia-arachnoid
autonomic nervous system
nerves that control involuntary body functions of muscles, glands, and internal organs
sciatic nerve
nerve extending from the base of the spine down the thigh, lower leg, and foot
sciatica
is pain or inflammation along the course of the nerve
cerebell/o
cerebellum
cerebr/o
cerebrum
dur/o
dura mater
encephal/o
brain
gli/o
glial cells
lept/o
thin, slender
mening/o and meningi/o
membranes, meninges
subdural hematoma
results from the tearing of veins between the dura and arachnoid membranes, often a result of blunt trauma
epidural hematoma
occurs between the skull and the dura as the result of a ruptured meningeal artery, usually after a fracture of the skull
intracerebral hematoma
caused by bleeding directly into brain tissue, such as can occur in the case of uncontrolled hypertension (high blood pressure)
my/o
muscle
myel/o
spinal cord (means bone marrow in other contexts)
neur/o
nerve
pnt/o
pons
radicul/o
nerve root (of spinal nerves)
thalam/o
thalamus
thec/o
sheath (refers to the meninges)
bag/o
vagus nerve (10th cranial nerve)
alges/o
excessive sensitivity to pain
-algesio
excessive sensitivity to pain
polyneuropathies
affect many nerves
mononeuropathies
affect individual nerves
-algia
pain
caus/o
burning
comat/o
deep sleep (coma)
esthesi/o
feeling, nervous sensation
-esthesia
feeling, nervous sensation
kines/o, kinesi/o
movement
-kinesia, -kinesis, -kinetic
movement
-lepsy
seizure
lex/o
word, phrase
-paresis
weakness
-phasia
speech
-plegia
paralysis (loss or impairment of the ability to move parts of the body)
-praxia
action
-sthenia
strength
syncop/o
to cut off, cut short
tax/o
order, coordination
sympathetic nerves
involuntary nerves that stimulate the body in times of stress or crisis
parasympathetic nerves
involuntary, autonomic nerves that regulate normal body functions such as heart rate, breathing, and muscle of the gastrointestinal tract
synapse
the microscopic space through which an impulse is transmitted
in the peripheral system, how many pairs of cranial nerves and spinal nerves are there?
12 and 31
hydrocephalus
abnormal accumulation of fluid (CSF) in the brain
spina bifida
congenital defects in the lumbar spinal column caused by imperfect union of vertebral parts (neural tube defect)
spina bifida cystica
a more severe form with cyst-like protrusions
miningocele
meninges protrude to the outside of the body
myelomeningocele
both spinal cord and meninges protrude
alzheimer disease (AD)
brain disorder marked by gradual and progressive mental deterioration (dementia), personality changes, and impairment of daily functioning
senile plaques
neurofibrillary tangles
bundles of fibrils in the cytoplasm of a neuron
amyloid
a protein
amyotrophic lateral sclerosis (ALS)
degenerative disorder of motor neurons in the spinal cord and brainstem aka Lou Gehrig disease
epilepsy
chronic brain disorder characterized by recurrent seizure activity
aura
proceeds a seizure, which is a peculiar sensation experienced by the affected person before onset of a seizure e.g., dizziness and numbness
absence seizures
a form of a seizure consisting of momentary clouding of consciousness and loss of awareness of a person’s surroundings
tonic-clonic seizures (grand mal or ictal events)
characterized by a sudden loss of consciousness, falling down, and then tonic contractions (stiffening of muscles) followed by clonic contractions (twitching and jerking movements of the limbs)
petit mal seizures
common in children, another name for absence seizures
temporal lobe epilepsy
seizures begin in the temporal lobe, on each side of the brain near the ears
complex partial seizure
most common type, complex means impaired consciousness and complex means not generalized, commonly these patients have seizures that cause them to pause whatever they are doing and become confused and have memory problems
huntington disease (huntington chorea)
hereditary disorder marked by degenerative changes in the cerebrum leading to abrupt involuntary movements and mental deterioration with a shuffling gait
multiple sclerosis (MS)
destruction of the myelin sheath on neurons in the CNS and its replacement by plaques of sclerotic (hard) tissue
gait
manner of walking
myasthenia gravis (MG)
autoimmune neuromuscular disorder characterized by weakness of voluntary muscles
palsy
paralysis (partial or complete loss of motor function)
cerebral palsy
is the partial paralysis and lack of muscular coordination caused by loss of oxygen (hypoxia) or blood flow to the cerebrum during pregnancy or in the perinatal period
Bell palsy
is paralysis on one side of the face
parkinson disease (parkinsonism)
degeneration of neurons in the basal ganglia, occurring in later life and leading to tremors, weakness of muscles, and slowness of movement
tourette syndrome
involuntary, spasmodic, twitching movements; uncontrollable vocal sounds; and inappropriate words and is associated with an excess of or hypersensitivity to dopamine
tics
involuntary movements, usually beginning with twitching of the eyelid and muscles of the face with verbal outbursts
herpes zoster (shingles)
viral infection affecting peripheral nerves
meningitis
inflammation of the meninges; leptomeningitis
human immunodeficiency virus (HIC) encephalopathy
brain disease and dementia occurring with AIDS
brain tumor
abnormal growth of brain tissue and meninges
gliomas
most primary brain tumors arise from glial cells or meninges (meningiomas)
cerebral edema
tumors can cause swelling and hydrocephalus
cerebral concussion
type of traumatic brain injury caused by a blow to the head
cerebral contusion
bruising of brain tissue as a result of direct trauma to the head
cerebrovascular accident (CVA)
disruption in the normal blood supply to the brain; stroke
stroke aka cerebral infarction
is the result of impaired oxygen supply to the brain
what are the 3 different types of strokes?
- thrombotic 2. hemorrhagic 3. embolic
thrombotic stroke
blood clot (thrombus) in the arteries leading to the brain resulting in occlusion (blocking) of the vessel
What does TIAs stand for?
Transient Ischemic Attacks
hemorrhagic stroke
caused by cerebral arterial wall rupture
embolic stroke
caused by an embolus (dislodged thrombus) that travels to cerebral arteries and occludes a small vessel
What does tPA stand for?
Tissue Plasminogen Activator
migraine
severe, recurring, unilateral, vascular headache
cerebrospinal fluid analysis
samples of CSF are examined
cerebral angiography
x-ray imaging of the arterial blood vessels in the brain after injection of contrast material
Computed tomography (CT) of the brain
computerized x-ray technique that generates multiple images of the brain and spinal cord
magnetic resonance imaging (MRI)
magnetic field and pulses of radiowave energy create images of the brain and spinal cord
positron emission tomography (PET) scan
radioactive glucose is injected and then detected in the brain to image the metabolic activity of cells
doppler ultrasound studies
sound waves detect blood flow in the carotid and intracranial arteries
electroencepalography (EEG)
recording of the electrical activity of the brain
lumbar puncture (LP)
CSF is withdrawn from between two lumbar vertebrae for analysis
stereotactic radiosurgery
use of a specialized instrument to locate and treat targets in the brain
Gamma Kinfe
a high-energy radiation beam
What does PSRS stand for?
Proton Stereotactic Radiosurgery
Dyskinesia
the medical term for abnormal, involuntary, spasmodic movement
informal name for a lumbar puncture?
spinal tap
What does the treatment of hydrocephalus involve?
The use of a shunt to drain the excess cerebrospinal fluid
what is a treatment for parkinson disease?
placement of electrodes in the brain
a disorder that usually recovers spontaneously
bell palsy
myelomeningocele
the protrusion of the meninges and spinal cord through a defect in the spinal column
Analgesic medication
to relieve postoperative pain
The first part of the nerve cell to receive the impulse is the
dendrite
